import easygui as g
import sys
import  os
filepath=g.fileopenbox(title='请选择一个文本文件：',default='.\\*.txt',filetypes=['*.txt'])
with open(filepath) as old_file:
    title=os.path.basename(filepath)
    msg='文件【%s】的内容如下：'%title
    text=old_file.read()
    text_after=g.textbox(msg,title,text)
if text !=text_after[:-1]:
    choice=g.buttonbox('检测到文件内容发生改变，请选择以下操作：','警告',('覆盖保存','放弃保存','另存为...'))
    if choice=='覆盖保存':
        with open(filepath,'w') as old_file:
            old_file.write(text_after[:-1])
    if choice=='放弃保存':
        pass
    if choice=='另存为...':
        another_path=g.filesavebox(default='.txt')
        if os.path.splitext(another_path)[1]!='.txt':
            another_path+='.txt'
        with open(another_path,'w') as new_file:
            new_file.write(text_after[:-1])